The invention concerns a connecting device for quick, releasable connection and locking of a first body to a second body, for example a freight component to a support rail or bar which is fixedly installed in an aircraft.
The usual practice is for freight containers or pallets to be anchored to the floor of the freight compartment in an aircraft by means of locking arrangements including connecting devices which are quick to close and open and by means of which the freight containers or pallets can be fitted into holding components such as support rails or bars which are let into the floor of the freight compartment, and there anchored in position by a locking action. For reasons, of saving weight, the support bars generally consist of aluminum, while at least the parts of the connecting devices which are fixedly connected to the locking arrangements and which under some circumstances are required to carry high forces are made from materials which can appropriately carry the loadings involved, for example high-quality steel.
Although the above-discussed situation represents a preferred area of use of the connecting device according to the present invention, it will be noted at this point that connecting devices constructed in accordance with the invention can be used wherever first and second bodies are to be connected and locked together in a similar fashion to that described above. It will be seen that, in that respect, the only important consideration is that one of the two bodies is fixedly connected to the housing of the connecting device at least during the period of use while the other body has a holding means, which corresponds to the above-mentioned support bar, having a receiving opening into which a head portion of a locking pin of the connecting device can be introduced in an initial position, and against the edge regions of which that head portion can bear in locking relationship in a direction which is generally opposite to the direction of introduction, when the head portion, after having been introduced, has been turned through a given angle, for example 90.degree..
In order for a connecting device to operate in a situation as just discussed above, the known connecting device has a housing in which a locking pin is mounted in such a way that, besides the above-mentioned rotary movement, it can also perform a controlled axial movement. For that purpose the locking pin is provided at its end remote from the locking head with a two-armed lever which is pivotable about a shaft or spindle mounted on the locking pin and extending transversely to the longitudinal axis thereof. The one arm of the lever, which is longer than the other arm, is in the form of a handle while the other substantially shorter arm forms a cam disk portion acting with its peripheral edge on a disk portion which is arranged perpendicularly to the longitudinal axis of the locking pin and concentrically surrounds same. The last-mentioned disk portion is freely displaceable relative to the locking pin at least in the axial direction and bears against the housing by way of plate springs, on the side of the disk portion which is remote from the cam disk portion.
In that arrangement the two-armed lever can be pivoted from a first position in which the handle extends approximately in the longitudinal direction of the locking pin, into a second position in which the handle is disposed at an angle of 90.degree. relative to the longitudinal axis of the locking pin. The peripheral edge of the cam disk portion is such that its part which acts on the transversely disposed disk portion is at a smaller position from the pivot axis, in the first position, than that part which acts on the transversely disposed disk portion in the second position. By virtue of that arrangement, the spacing between the transversely disposed disk portion and the pivot axis is increased by the pivotal movement of the two-armed lever into the second position in which the handle is at an angle of 90.degree. relative to the longitudinal axis of the locking pin. As the transversely disposed disk portion cannot in practice move downwardly against the force of the plate springs supporting it, instead the pivot axis and the locking pin, which is rigidly connected thereto, must move in the opposite direction upwardly, that is to say, in such a way that its locking head, which is disposed at the other end of the locking pin is pressed by way of two projecting flange regions against a support portion of the support bar.
That device is actuated in such a way that firstly, when the handle is set in the up position, the locking pin is rotated about its longitudinal axis into such a position that its locking head, which is of a radially asymmetrical configuration, can be introduced through a suitably shaped receiving opening in the support bar. The locking pin is then turned through 90.degree. in such a way that, as described above, its locking head engages against edge regions of the receiving opening and can therefore no longer come out of that opening, in the opposite direction to the direction of introduction. Then, with the arrangement in that condition, the handle is pivoted into its second position in order to move the locking pin in the opposite direction to the direction of introduction, whereby the locking head is pressed against the support portion of the support bar, and the above-mentioned plate springs are tightened.
That arrangement suffers from the disadvantage that, both when the connection is being made between the two bodies and when such a connection is being released, the operator is required to perform two different movements, namely a rotary movement of the locking pin about its longitudinal axis and a pivotal movement of the two-armed lever about the pivot axis which extends transversely to the longitudinal axis of the locking pin. A particular disadvantage in that respect is that only an extremely short lever arm is available for performing the first-mentioned rotary movement about the longitudinal axis of the locking pin, as that rotary movement is effected when the handle portion of the two-armed lever is extending in the longitudinal direction of the locking pin. The operator will therefore tend already to pivot the two-armed lever downwardly through a certain angle during the rotary movement of the locking pin so that the rotary movement can be more easily performed. However, that pivotal movement of the lever means that the locking pin is already drawn upwardly in the opposite direction to the direction of introduction thereof, so that there is the risk that, during the rotary movement involving going from the starting position into the locking position, the locking pin skids along with the upward surfaces of its locking head against the underside of the edge regions of the receiving opening in the support bar, the edge regions forming the support portion against which the locking head bears. A corresponding consideration also applies in regard to the oppositely directed rotary movement out of the locking position into the initial position of the arrangement, when releasing the connecting device. As the locking pin with its head is made from material which can carry high loadings, such as for example high-quality steel, the above-indicated phenomena can result in very severe abrasive wear at the underneath surfaces of the edge regions of the receiving opening of the support bar which is of aluminium.